/*
Copyright (C) 1996-2001 Id Software, Inc.
Copyright (C) 2002-2009 John Fitzgibbons and others
Copyright (C) 2010-2014 QuakeSpasm developers

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/
//gl_warp.c -- warping animation support

#include "q_defs.h"

extern cvar_t r_drawflat;

cvar_t r_oldwater = {"r_oldwater", "0", CVAR_ARCHIVE};
cvar_t r_waterquality = {"r_waterquality", "8", CVAR_NONE};
cvar_t r_waterwarp = {"r_waterwarp", "1", CVAR_NONE};

int32_t gl_warpimagesize;
float load_subdivide_size; //johnfitz -- remember what subdivide_size value was when this map was loaded

float   turbsin[] =
{
#include "gl_warp_sin.h"
};

#define WARPCALC(s,t) ((s + turbsin[(int32_t)((t*2)+(cl.time*(128.0/PI))) & 255]) * (1.0/64)) //johnfitz -- correct warp
#define WARPCALC2(s,t) ((s + turbsin[(int32_t)((t*0.125+cl.time)*(128.0/PI)) & 255]) * (1.0/64)) //johnfitz -- old warp

//==============================================================================
//
//  OLD-STYLE WATER
//
//==============================================================================

extern  qmodel_t        *loadmodel;

msurface_t      *warpface;

cvar_t gl_subdivide_size = {"gl_subdivide_size", "128", CVAR_ARCHIVE};

void BoundPoly(int32_t numverts, float *verts, vec3_t mins, vec3_t maxs)
{
	int32_t         i, j;
	float   *v;

	mins[0] = mins[1] = mins[2] = 999999999;
	maxs[0] = maxs[1] = maxs[2] = -999999999;
	v = verts;
	for(i = 0 ; i < numverts ; i++)
		for(j = 0 ; j < 3 ; j++, v++)
		{
			if(*v < mins[j])
				mins[j] = *v;
			if(*v > maxs[j])
				maxs[j] = *v;
		}
}

void SubdividePolygon(int32_t numverts, float *verts)
{
	int32_t         i, j, k;
	vec3_t  mins, maxs;
	float   m;
	float   *v;
	vec3_t  front[64], back[64];
	int32_t         f, b;
	float   dist[64];
	float   frac;
	glpoly_t        *poly;
	float   s, t;

	if(numverts > 60)
		Sys_Error("numverts = %" PRIi32, numverts);

	BoundPoly(numverts, verts, mins, maxs);

	for(i = 0 ; i < 3 ; i++)
	{
		m = (mins[i] + maxs[i]) * 0.5;
		m = gl_subdivide_size.value * floor(m / gl_subdivide_size.value + 0.5);
		if(maxs[i] - m < 8)
			continue;
		if(m - mins[i] < 8)
			continue;

		// cut it
		v = verts + i;
		for(j = 0 ; j < numverts ; j++, v += 3)
			dist[j] = *v - m;

		// wrap cases
		dist[j] = dist[0];
		v -= i;
		VectorCopy(verts, v);

		f = b = 0;
		v = verts;
		for(j = 0 ; j < numverts ; j++, v += 3)
		{
			if(dist[j] >= 0)
			{
				VectorCopy(v, front[f]);
				f++;
			}
			if(dist[j] <= 0)
			{
				VectorCopy(v, back[b]);
				b++;
			}
			if(dist[j] == 0 || dist[j + 1] == 0)
				continue;
			if((dist[j] > 0) != (dist[j + 1] > 0))
			{
				// clip point
				frac = dist[j] / (dist[j] - dist[j + 1]);
				for(k = 0 ; k < 3 ; k++)
					front[f][k] = back[b][k] = v[k] + frac * (v[3 + k] - v[k]);
				f++;
				b++;
			}
		}

		SubdividePolygon(f, front[0]);
		SubdividePolygon(b, back[0]);
		return;
	}

	poly = Hunk_AllocName(sizeof(glpoly_t) + (numverts - 4) * VERTEXSIZE * sizeof(float), __func__);
	poly->next = warpface->polys->next;
	warpface->polys->next = poly;
	poly->numverts = numverts;
	for(i = 0 ; i < numverts ; i++, verts += 3)
	{
		VectorCopy(verts, poly->verts[i]);
		s = DotProduct(verts, warpface->texinfo->vecs[0]);
		t = DotProduct(verts, warpface->texinfo->vecs[1]);
		poly->verts[i][3] = s;
		poly->verts[i][4] = t;
	}
}

/*
================
GL_SubdivideSurface
================
*/
void GL_SubdivideSurface(msurface_t *fa)
{
	vec3_t  verts[64];
	int32_t         i;

	warpface = fa;

	//the first poly in the chain is the undivided poly for newwater rendering.
	//grab the verts from that.
	for(i = 0; i < fa->polys->numverts; i++)
		VectorCopy(fa->polys->verts[i], verts[i]);

	SubdividePolygon(fa->polys->numverts, verts[0]);
}

/*
================
DrawWaterPoly -- johnfitz
================
*/
void DrawWaterPoly(glpoly_t *p)
{
	float   *v;
	int32_t         i;

	if(load_subdivide_size > 48)
	{
		glBegin(GL_POLYGON);
		v = p->verts[0];
		for(i = 0 ; i < p->numverts ; i++, v += VERTEXSIZE)
		{
			glTexCoord2f(WARPCALC2(v[3], v[4]), WARPCALC2(v[4], v[3]));
			glVertex3fv(v);
		}
		glEnd();
	}
	else
	{
		glBegin(GL_POLYGON);
		v = p->verts[0];
		for(i = 0 ; i < p->numverts ; i++, v += VERTEXSIZE)
		{
			glTexCoord2f(WARPCALC(v[3], v[4]), WARPCALC(v[4], v[3]));
			glVertex3fv(v);
		}
		glEnd();
	}
}

//==============================================================================
//
//  RENDER-TO-FRAMEBUFFER WATER
//
//==============================================================================

/*
=============
R_UpdateWarpTextures -- johnfitz -- each frame, update warping textures
=============
*/
void R_UpdateWarpTextures(void)
{
	texture_t *tx;
	int32_t i;
	float x, y, x2, warptess;

	if(r_oldwater.value || cl.paused || r_drawflat_cheatsafe || r_lightmap_cheatsafe)
		return;

	warptess = 128.0 / CLAMP(3.0, floor(r_waterquality.value), 64.0);

	for(i = 0; i < cl.worldmodel->numtextures; i++)
	{
		if(!(tx = cl.worldmodel->textures[i]))
			continue;

		if(!tx->update_warp)
			continue;

		//render warp
		GL_SetCanvas(CANVAS_WARPIMAGE);
		GL_Bind(tx->gltexture);
		for(x = 0.0; x < 128.0; x = x2)
		{
			x2 = x + warptess;
			glBegin(GL_TRIANGLE_STRIP);
			for(y = 0.0; y < 128.01; y += warptess) // .01 for rounding errors
			{
				glTexCoord2f(WARPCALC(x, y), WARPCALC(y, x));
				glVertex2f(x, y);
				glTexCoord2f(WARPCALC(x2, y), WARPCALC(y, x2));
				glVertex2f(x2, y);
			}
			glEnd();
		}

		//copy to texture
		GL_Bind(tx->warpimage);
		glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, glx, gly + glheight - gl_warpimagesize, gl_warpimagesize, gl_warpimagesize);

		tx->update_warp = false;
	}

	// ericw -- workaround for osx 10.6 driver bug when using FSAA. R_Clear only clears the warpimage part of the screen.
	GL_SetCanvas(CANVAS_DEFAULT);

	//if warp render went down into sbar territory, we need to be sure to refresh it next frame
	if(gl_warpimagesize + sb_lines > glheight)
		Sbar_Changed();

	//if viewsize is less than 100, we need to redraw the frame around the viewport
	scr_tileclear_updates = 0;
}